"DOCUMENTATION OF THE BASIS FOR SELECTION OF THE CONTENTS OF CHAPTER 3 - ASTM DISTILLATION@ TRUE BOILING POINT DISTILLATION@ AND EQUILIBRIUM FLASH VAPORIZATION RELATIONSHIPS FOR PETROLEUM FRACTIONS IN ""TECHNICAL DATA BOOK - PETROLEUM REFINING"""
INTRODUCTION The two distillation procedures for characterizing petroleum fractions are the ASTM method (American Society for Testing and Materials) and the True Boiling Point (TBP) method. Both are analytical in nature and are used to define the volatility characteristics of petroleum and other complex mixtures. The two distillations are both of a batch type but differ from each other mainly in the degree of fractionation. The true boiling point distillation is run in a packed column at a relatively high reflux ratio to insure a high degree of fractionation. The ASTM distillation (1) is run in an Engler flask without a packed section@ so the only reflux results from heat loss through the neck of the flask. The ASTM distillation is the more widely used because it is simpler and less expensive to run@ requires less sample@ and consumes only about one-tenth the time of the TBP distillation. Furthermore@ ASTM distillations are standardized@ whereas TBP distillations vary appreciably in procedure and apparatus.